Pneumatic tube carrier detector assembly with cam operated microswitch and resilient finger heeler means

ABSTRACT

A pneumatic tube carrier detector having a generally air-tight housing is mounted on a tube. A cam having a straight cam surface extending between a pair of curved cam surfaces is pivotally mounted within the housing and is movable between at-rest and deflected positions. A carrier contact finger formed of flexible, semi-rigid wear resistant material is mounted on the cam diametrically opposite of the straight cam surface and extends through an opening in the pneumatic tube into the path of a moving carrier. A limit switch is mounted within the housing and has a lever arm which is engaged with the straight cam surface when the cam is in the at-rest position. The lever arm moves along the straight cam surface to actuate the switch when the projecting contact finger is struck by a moving carrier and pivots the cam. The switch arm moves along one of the curved cam surfaces, depending upon the carrier direction, after the switch has been actuated to provide override protection for the switch arm as the cam continues to rotate. A spring returns the cam to the at-rest position after rotating by a moving carrier.

United States Patent Kryah et al.

[75] Inventors: John C. Kryah; Charles B. Barnett,

both of Akron, Ohio Feb. 18,1975

Primary Examiner-James R. Scott Attorney, Agent, or FirmFrease & Bishop [57] ABSTRACT A pneumatic tube carrier detector having a generally air-tight housing is mounted on a tube. A cam having a straight cam surface extending between a pair of curved cam surfaces is pivotally mounted within the housing and is movable between at-rest and deflected positions. A carrier contact finger formed of flexible, semi-rigid wear resistant material is mounted on the cam diametrically opposite of the straight cam surface and extends through an opening in the pneumatic tube into the path of a moving carrier. A limit switch is mounted within the housing and has a lever arm which is engaged with the straight cam surface when the cam is in the at-rest position. The lever arm moves along the straight cam surface to actuate the switch when the projecting contact finger is struck by a moving carrier and pivots the cam. The switch arm moves along one of the curved cam surfaces, depending upon the carrier direction, after the switch has been actuated to provide override protection for the switch arm as the cam continues to rotate. A spring returns the cam to the at-rest position after rotating by a moving carrier.

13 Claims, 8 Drawing Figures [73] Assignee: Diebold, Incorporated, Canton,

Ohio

[22] Filed: Nov. 7, 1973 [21] Appl. No.: 413,612

[52] U.S. Cl ZOO/61.41, 200/153 LB, 243/36 [51] Int. Cl H01h 3/16, B65g 51/36 [58] Field of Search ZOO/61.4, 61.41, 61.42, 200/6158 R, 81 R, 81.9 R, 81.9 M, 82 R, 82 D, 153 M, 153 L, 153 LB, 329, 331, 332, 335, 337, 338; 74/567; 174/110 EC, 120 R, 120 C, 120 AR, 121 R; 243/1, 29, 36, 38, 39

[56] References Cited UNITED STATES PATENTS 589,832 9/1897 Hook ZOO/61.41 2,547,765 4/1951 2,698,363 12/1954 3,202,779 8/1965 3,274,351 9/1966 3,486,961 12/1969 3,772,604 4/1973 Groff et al. ZOO/81.9 R

FOREIGN PATENTS OR APPLICATIONS 682,236 9/1939 Germany 243/36 1 l l l l I 1 9 J l 8 I ll 11 22 l 28 L3 r"-" [l i, 15 J ll 1 F PATENIEB FEB 1 8 m SHEET 1 OF 2 FIG.

FIG.3

PATENTED 3197'- SHEET 2 BF FIG.4

PNEUMATIC TUBE CARRIER DETECTOR ASSEMBLY WITH CAM OPERATED MICROSWITCH AND RESILIENT FINGER HEELER MEANS BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to detector constructions and in particular to detectors for use in a pneumatic tube system for detecting the passage of a carrier. More particularly, the invention relates to a carrier detector construction having a carrier contact finger projecting partially into the pneumatic tube which is able to withstand repeated forceful rapidly moving carrier contact without permanent deformation, and which detector is of an extremely simple construction which reduces repair and maintenance problems and costs.

2. Description of the Prior Art There are numerous styles, types and arrangements of detectors having a projecting member which collides with or is struck by a moving object and actuates a switch for indicating the passage of the object past the detector, such as shown in U.S. Pat. Nos. 2,610,342, 2,658,967 2,698,363, 3,202,779 and 3,274,351. Likewise, there are detector structures for specific use in pneumatic tube systems for indicating the passage of a carrier, an early example of which is U.S. Pat. No. 589,832.

Many of these prior detector constructions have a lever or finger which projects into the path of the moving object and upon contact with the moving object is pivoted out of the objects path and trips a switch or actuates other types of signaling devices. Springs generally are used to return the projecting lever to its at-rest position after passage of the object and absorb much of the impact force of the moving object. Known contact members usually are formed of a rigid material such as spring steel or the like, in order to withstand the high impact force of or collision with the moving object, especially in those installations where the object is moving at a high rate of speed, such as in a pneumatic tube system.

Difficulties have long existed in carrier detector constructions used in pneumatic tube systems, in that the projecting carrier contact member is unable to withstand the repeated high impact forces without permanent deformation and destruction thereof. This requires considerable rnaintenance, repair and replacement of the contact member and associated switch mechanism, which in many installations are located at places not readily accessible for repairs.

Many pneumatic tube carrier detectors use a cantilever type contact member, such as shown in U.S. Pat. No. 589,832, which is held in operating position by a spring mechanism, which spring also returns the contact member to at-rest position after actuation by the passing carrier. These springs are subjected to high impact forces and require frequent replacement. Likewise, the cantilever type arrangement due'to its unbalanced mounting present another operationg problem. When leaks developed in the detector housing, the air flow, either vacuum or pressure produced, upon moving past the cantilever contact member through the leak opening may pivot the lever and prematurely actuate the associated switch causing a false signal to be transmitted.

Prior carrier contact members, due to the stiffness of the material required to be able to withstand the high impact force without destruction and deformation, very often marked and defaced the passing carrier as well as impeding somewhat, the carrier progress through the tube.

Prior detector constructions also have the disadvan tage of being mounted in only a single position on the pneumatic tube to enable the projecting contact mentber to operate satisfactorily. Likewise, the excess length of the contact member extending from its connecting cam or mounting means of many prior detectors multiplies considerably the force exerted by the carrier through the contact member on the attaching cam resulting in breakage at the cam connection zone. Furthermore, the contact area of the contact member in some installations is considerably broad to achieve sufficient strength, which increases even more the force needed to be absorbed by the lever and connecting cam and increases wear on the carrier.

The stiffness of the carrier contact member of prior detector constructions has the disadvantage of absorbing very little energy of the impact force, and transmits the majority of this force through the contact member to the switch actuation mechanism. This transmitted impact force is considerably greater than the amount of force necessary to actuate an indicating switch, thus requiring the indicating switch to absorb a considerably larger amount of energy than necessary, resulting in the frequent repair and replacement of the switch actuation mechanism.

Most of these prior constructions require accurate alignment and installation in the field to achieve the correct setting factor in order to insure actuation ofthe indicating switch when contacted by a passing carrier. Furthermore, many detectors require readjustment when the pneumatic tube air system is switched from vacuum to pressure, and thus are unsatisfactory for use in many of todays pneumatic systems where the air flow is constantly being changed depending upon the direction of carrier travel. Likewise, known carrier detectors for use with pneumatic tubes in which the carriers move in both directions through the tube require two separate switches or switch arms which are actuated individually by a single or double cam depending upon the carrier direction.

Thus, a need has existed for a simple, rugged pneumatic tube carrier detector which is able to withstand repeated high impact forces of a carrier traveling in either direction through the tube, which is operable under either vacuum or pressure operating conditions without requiring readjustment, which provides the flexibility and shock absorbing qualities needed for proper operation without permanent deformation or destruction of the projecting contact member after repeated use, and which eliminates the difficulties and problems encountered with prior known devices.

SUMMARY OF THE INVENTION Objectives of the invention include providing a pneumatic tube carrier detector construction which has a pivotally mounted symmetrically shaped, balanced cam which actuates a switch upon passage of a carrier in either direction through the tube, which carrier contacts a finger extending from the cam into the pneumatic tube to pivot the switch actuating cam; providing such a detector construction in which the contact finger is formed of elastomer impregnated woven fabric which is sufficiently rigid to maintain its desired shape and position within the tube, which is sufficiently flexible to provide the shock absorbing qualities able to withstand repeated high impact forces without permanent deformation or destruction, and which absorbs a large part of the impact energy when struck by a moving carrier eliminating transmission of this energy to the switch actuation mechanism, resulting in increased wear life and efficiency of the switch mechanism; providing such a detector construction in which the can has a flat surface extending between a pair of curved cam surfaces, in which the flat surface normally engages the switch when the cam is at rest and upon pivotal movement of the cam upon passage of a carrier actuates the switch, and in which curved cam surface means provides override protection for the switch actuation mechanism; providing such a detector construction which can be mounted in various positions on a pneumatic tube without affecting the operation thereof since the contact finger does not depend upon gravity for its operation, in which the contact finger has a relatively short length between the point of carrier contact and its connection to the cam, thus decreasing the impact force transmitted to the cam connection; providing such a detector construction which is operable under either vacuum or pressure conditions in the tube without requiring readjustment, and which permits mounting tolerances in the field and can compensate for minor misalignment between the cam and switch without affecting the operation thereof; and providing a carrier detector construction which eliminates difflculties heretofore encountered, achieves the stated objectives simply, efficiently and economically, reduces maintenance and repairs, and solves problems and satisfies existing needs.

These objectives and advantages are obtained by the detector construction for detecting carrier moving through a pneumatic tube, the general nature of which may be stated as including generally airtight housing means mounted on the pneumatic tube covering a slot formed in the tube; cam means; pin means pivotally mounting the cam means within the housing means for rotation between at-rest and deflected positions; switch means engageable with the cam means and actuated thereby when the cam means rotates between at-rest and a deflected position; finger means mounted on the cam means and extending through the tube slot into the interior of the tube for contact by a carrier moving in either direction through the tube to rotate the cam means to a deflected position; the finger means being formed ofa flexible, semi-rigid, elastomer impregnated woven fabric whereby the lever means has sufficient flexibility to absorb the carrier impact and sufficient rigidity to rotate the cam means when the finger means is struck by a moving carrier; the cam means including hub means through which the pivot pin means is journaled, a flat cam surface spaced from the axis of the pivot pin means and a pair of curved cam surfaces interrupted or separated by said flat surface; the switch means including a lever arm engaging the flat cam surface when the cam means is in the at-rest position; the switch means lever arm being moved by the flat cam surface to actuate the switch means when the finger means is struck by a moving carrier to move the cam means between at-rest and a deflected position; the lever arm engaging one of the curved cam surfaces after actuation of the switch means preventing continued movement of the lever arm by the continued rotation of the cam means; and spring means operatively connected to the cam means to return the cam means to at-rest position from a deflected position after passage of a carrier.

BRIEF DESCRIPTION OF THE DRAWINGS A preferred embodimennt of the invention illustrative of the best mode in which applicants have contemplated applying the principles is set forth in the following description and shown in the drawings and is particularly and distinctly pointed out and set forth in the appended claims.

FIG. 1 is a general diagrammatic view ofa simple two station pneumatic tube system utilizing the improved carrier detector construction;

FIG. 2 is a top plan view with portions broken away, of the detector construction mounted on a pneumatic tube;

FIG. 3 is a side elevation with portions broken away and in section, of the detector construction shown in FIG. 2;

FIG. 4 is a sectional view taken on line 44, FIG. 3;

FIG. 5 is a general diagrammatic view showing the detector construction in deflected position upon passage of a carrier;

FIG. 6 is a general diagrammatic view similar to FIG. 5 showing the detector construction in deflected position with the carrier moving in the opposite direction of that shown in FIG. 5;

FIG. 7 is a top plan view of the detector cam looking in the direction of arrows 7-7, FIG. 3; and

FIG. 8 is a sectional view taken on line 8-8, FIG. 7.

Similar numerals refer to similar parts throughout the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT A simplified pneumatic tube system is shown diagrammatically. in FIG. 1 and includes a pair of spaced terminals 1 and 2 connected by a pneumatic tube 3. The improved carrier detector construction orunit is indicated at 4, and is shown'mounted on pneumatic tube 3 adjacent carrier terminal 2 for giving a signal of the arrival of a carrier at the terminal, and another unit is shown at the midpoint between terminals of the detector construction 4 may be used at numerous locations throughout a pneumatic tube system as shown in FIG. 1, such as adjacent terminals, at branch Y tube sections, at carrier transfer mechanisms, etc. to transmit signals to a remote location, whereby the condition of the tube system and location of carriers therein can be readily ascertained.

Detector 4 (FIGS. 2, 3 and 4) includes a generally airtight housing 5 formed by top wall 6, sloping side walls 7 and 8, and end walls 9 and 10. Side and end walls 7-10 terminate in a bottom circumferential flange II. A support platform 12 having a flat housing supporting surface 13 is mounted on tube 3 for supporting housing 5. Platform 12 has a pair of longitudinally extending side flanges 14 which terminate in a pair of short transversely extending end flanges 15. As elongated slot 17 is formed in platform surface 13 and aligns with an axially extending slot 18 formed in the wall of tube 3 beneath housing 5, the purpose of which is discussed below.

Platform 12 is secured to tube 3 by tack welds 19 at the junction of tube 3 and end flanges 15. A sealing compound 20 is injected between platform surface 13 and tube 3 surrounding tube slot 18 to form an airtight connection between platform 12 and tube 3.

A gasket 21 is placed between platform surface 13 and housing flanges 11 to provide an airtight seal therebetween when housing 5 is clamped by bolts 22 to surface 13. Bolts 22 extend through reinforced bosses 28 formed at the corners of housing 5 in flange 11.

A vertically extending bracket 23 is mounted within housing 5 and includes a vertical plate 24 which terminates in a pair of outwardly oppositely extending upper and lower flanges 25 and 26 respectively. Upper flange 25 is approximately one-half the length of lower flange 26 as shown in FIG. 3, due to notch 16 formed in the upper right-hand corner of plate 24. Bracket 23 is mounted within housing 5 by a pair of bolts 27 which clamp lower bracket flange 26 to platform surface 13 (FIGS. 2 and 4).

A shim plate 29 may be inserted between lower flange 26 and platform surface 13 (FIG. 4), during the initial installation of detector 4 to provide adjustment and compensation due to wear of the carrier contact member.

In accordance with the invention a symmetrically shaped, balanced cam 30 is pivotally mounted by a pin 31 which in turn is mounted on the lower portion of bracket plate 24 by nut 31a and projects outwardly therefrom. Cam 30 is aligned with and spaced above aligned platform and tube slots 17 and 18 (FIGS. 3 and 4). Cam 30 preferably is formed of rugged lightweight nylon and includes a flat cam surface 32 extending between and separating but connecting a pair of curved side cam surfaces 33 and 34. Cam surfaces 33 and 34 terminate and are joined integrally at their lower ends with a hub 35 by a pair of straight connecting members 38 and 39, respectively. Cam surfaces 33 and 34 lie on a radius of curvature having its center at the axis of pivot pin 31. Pivot pin 31 extends through hub 35 for pivotally mounting cam 30 on bracket 23.

A pair of reinforcing ribs 36 extend radially between hub 35 and the junctions between flat cam surface 32 and curved surfaces 33 and 34, and are formed integrally therewith. Flat cam surface 32 is spaced from pivot pin 31 which is eccentrically located with respect to cam surfaces 32, 33 and 34 as seen in FIG. 3. A pair of switch actuation indicating points 32a and 32b (FIGS. 3 and 7) are formed on flat cam surface 32 adjacent the ends thereof to assist field and factory personnel in setting switch 50 in position to insure satisfactory operation thereof. When in the cam at-rest position of FIGS. 2-4, flat surface 32 extends parallel with the axis of tube 3.

A pair of spaced ears 37 are formed integrally with and extend downwardly from hub 35 toward tube slot 18 and terminate just above the interior of tube 3 (FIGS. 3 and 4).

Further in accordance with the invention, a carrier contact finger 40 is secured between ears 37 by a pair of rivets 41 (FIG. 3). Finger 40 terminates in an inwardly tapered end portion 42 which extends beyond ears 37 and projects through slots 17 and 18 into the interior of tube 3 into the path of a carrier moving therethrough. Finger 40 is formed of an elastomer impregnated woven fabric, preferably neoprene impregnated cotton duck material such as sold under the trademark, Fabreeka, by Fabreeka Products Company of Boston, Mass. Finger 40 also may be formed of nylon or other woven material covered with Teflon or other synthetic material without departure from the invention. Finger 40, preferably is formed of two identical half-sections 40a and 40b which are clamped together by rivets 41 thereby increasing the flexibility of finger 40.

The elastomer impregnated woven fabric of finger 40 provides a flexible, semi-rigid member which has sufficient flexibility to absorb the carrier impact forces without permanently deforming finger 40. Likewise, this material provides sufficient rigidity and stiffness to prevent a carrier from moving past detector 4 without striking finger 40 and rotating the cam 30. Furthermore, finger 40 can withstand repeated operations without deformation or destruction due to the particular nature of the material forming finger 40.

Finger 40 extends radially from the axis of pivot pin 31, which is indicated by the line A. FIG. 4 in a diametrically opposite direction from flat cam surface 32. Cam 30 together with cars 37 and finger 40 is symmetrical about an imaginary plane (indicated at B, FIGS. 2 and 3) which passes through finger 40, axis A of pivot pin 31 and the midpoint of cam surface 32. Curved cam surfaces 33 and 34 are equal in length and radii of curvature, and are located on opposite sides of plane B.

A coil tension spring 43 extends between cam 30 and bracket 23 and is connected thereto by hook ends 44 and 45 which extend through openings 46 and 47 formed in flat cam surface 32 and in upper bracket flange 25, respectively. Spring 43 lies in plane B and is vertically aligned with axis A of pin 31 and contact finger 40, when cam 30 and finger 40 are in the at-rest position of FIG. 3. Thus, spring 43 maintains cam 30 and finger 40 in the at-rest position and returns them thereto after they are moved to a deflected position by a passing carrier. I I

Spring 43 exerts minimum tension on cam 30 when in the at-rest position and has a small degree of stiffness, thereby presenting minimum resistanceto the pivotal movement of cam 30 upon finger 40 being struck by a'passing carrier. Spring 43 insures the correct positioning of cam 30 when in at-rest position and returns cam 30 thereto from a deflected position, and is not intended to absorb the majority of the impact force as in many prior detector devices.

A usual limit switch 50 is mounted on the upper portion of bracket wall 24 by bolts 51 and includes a spring biased trip arm 52 and contact roller 53 mounted on the extended end thereof. Terminals 54 and 55 extend outwardly from switch 50 and are connected to usual wires 56 and 57 of an indicating and control system. Wires 56 and 57 extend through a grommet 58 mounted on platform surface 13 to provide a generally airtight exit from housing 5.

Switch roller 53 is engaged with the midpoint of flat cam surface 32 when cam 30 is in the at-rest position of FIG. 3, with contact finger 40 projecting into tube 3.

In operation, a usual pneumatic tube carrier 60 moving through tube 3 at a usual rate of speed strikes finger 40. Finger 40 flexes slightly to absorb much of the carrier impact force while retaining sufficient stiffness to swing upwardly through tube slot 18 pivoting cam 30 in a clockwise direction, as indicated by arrow C, FIG. 5. Switch roller 53 rides along flat cam surface 32 from its at-rest center position toward switch actuation point 32a adjacent the junction with curved surface 34 as cam 30 rotates. Cam surface 32 moves roller 53 upwardly vertically at a gradual rate as cam 30 rotates and upon reaching point 32a actuates switch 50 which transmits or breaks the appropriate carrier indicating signal.

Switch roller 53 does not engage cam points 320 and 32b but moves adjacent to and past these indicating points, as clearly shown in FIG. 4.

Cam 30 will continue to rotate in the clockwise direction after passage of carrier 60 until shoulder 61, formed at the junction of cam surface 33 and member 38, contacts stop 62, as shown by dot-dash lines in FIG. 5. Stop 62 is formed by a circumferential bead of sealing compound between the edges of slots 17 and 18 which insures an airtight seal between platform 12 and tube 3. Sealing compound 62 has a sound deadening effect and prevents cam 30 from striking metal stop means, such as the tube wall or platform 12 with the annoying sound that would be produced thereby. Roller 53 moves along curved surface 34 after actuation of switch 50 and prior to cam 30 striking stop 62, thereby maintaining the switch actuated positon without further upward movement of trip arm 52 which could cause damage thereto. Axis B of pivot pin 31 is the center of curvature of curved surface 34, thereby eliminating further upward movement of arm 52.

Spring 43 returns cam 30 to its at-rest position after passage of carrier 60, whereupon roller 53 returns to its usual at-rest position at the midpoint of cam surface 32 (FIG. 3). Trip arms 52, as well as spring 43, have a dampening effect on cam 30 to minimize oscillation thereof after finger 40 is struck by a passing carrier.

FIG. 6 illustrates diagrammatically the same operating sequence of detector 4 when carrier 60 is moving in the opposite direction through tube 3 as that shown in FIG. 5. Cam 30, upon finger 40 being struck by carrier 60, is pivoted in a counterclockwise direction with switch roller 53 moving along cam surface 31 past point 32b adjacent the junction with curved cam surface 33 to actuate switch 50. Switch roller 53, likewise will continue to move along curved cam surface 33 preventing damage to switch arm 52 until cam shoulder 63 contacts stop 62, as shown in dot-dash lines.

The improved construction of carrier detector 4 provides advantages not found in known prior detectors. The formation of contact finger 40 of the semi-rigid elastomer impregnated woven fabric material enables finger 40 to absorb the carrier impact forces by flexing sufficiently upon cantact, yet enables finger 40 to retain sufficient stiffness to prevent carrier 60 from moving past detector 4 without rotating cam 30 sufficiently to actuate switch 50. The unique arrangement of straight cam surface 32 located between curved cam surfaces 33 and 34 provides override protection to switch arm 52 preventing damage thereto, and eliminates exact alignment and mounting of switch 50 with respect to cam 30 since the at-rest positon of roller 53 can deviate from the midpoinnt of surface 32 along surface 32 on either side thereof without appreciably affecting the operation thereof. The short distance between the extended contact end 42 of finger 40 and its mounting point with cam 30 between tabs 37 does not multiply considerably the impact force exerted thereon by a passing carrier 60. The symmetrical, balanced configuration of cam 30, as illustrated in FIGS. and

6, enables detector 4 to function equally satisfactorily for carriers moving in either direction through tube 3. Furthermore, detector 4 need not extend verticallly upwardly from a carrier as shown in the drawings and described. Detector 4 can be mounted in a horizontally extending position, a downwardly vertically extending positon, or any position therebetween without affecting the operation since spring 43 will maintain cam 30 and contact finger 40 in the at-rest position, with the spring biasing of switch arm 52 maintaining roller 53 in contct with cam surface 32, regardless of the mounting position of detector 4.

Cam 30 preferably is formed of nylon or similar synthetic material which is extremely durable, sturdy, inexpensive and lightweight, and which provides sufficient low friction engagement with pivot pin 31 eliminating the need of bearings, bushings or the like. Likewise, spring 43 having a small degree of stiffness, easily absorbs the rotational force and impact of cam 30 without becoming weak or requiring freguent replacement as in prior constructions which must use a stiff spring to absorb the entire carrier impact force. Spring 43, likewise need not prevent rotation of cam 30 beyond the cam high points to prevent damage to the limit switch as in many prior devices, due to curved surfaces 33 and 34 and resilient stops 62, thereby eliminating critical and accurate switch alignment and settingfactors.

The symmetrical, balanced configuration of cam 30 is unaffected by the inrush or outflow of air into or out of tube 3 through slot 18 caused by leaks between housing 5 and tube 3 since such air flow would affect cam 30 equally about pivot pin 31 preventing premature rotation thereof in either direction. Likewise, the shifting of the air flow between vacuum and pressure will not cause premature rotation of cam.30 and actuation of switch 50 resulting in an erroneous signal being transmitted. This symmetrical configuration of cam 30 also eliminates the need for two switches in a dual directional pneumatic tube system as heretofore required by many prior detector constructions. The use of a single switch 50 in detector 4 does not permit the direction of carrier travel to be ascertained as in a two switch detector, but such information is not required in most pneumatic tube systems.

Simplicity, convenience and efficiency are enhanced further by the structural arrangement and minimum number of components of the detector construction within the housing, thereby reducing the maintenance and repair problems heretofore encountered with many known prior devices.

Accordingly, the construction is simplified, provides an effective, safe, inexpensive and efficient device which achieves all the enumerated objectives, provides foor eliminating difficulties encountered with prior devices and solves problems and obtains new results in the art.

In the foregoing description, certain terms have been used for brevity, clearness and understanding but no unnecessary limitations are to be implied therefrom beyond the requirements of the prior art, because such terms are used for descriptive purposes and are intended to be broadly construed.

Moreover, the description and illustration of the invention is by way of example, and the scope of the invention is not limited to the exact details of the construction shown or described.

Having now described the features, discoveries and principles of the invention, the manner in which the improved pneumatic tube carrier detector construction is constructed, assembled and operated, the characteristics of the new construction, and the advantageous, new and useful results obtained; the new and useful structures, devices, elements, arrangements, parts, and combinations are set forth in the appended claims.

We claim:

1. Detector construction for detecting the passage of a carrier moving through a pneumatic tube of a type in which a slot is formed in the tube including, generally airtight housing means mounted on the pneumatic tube covering the tube slot; cam means; pin means pivotally mounting the cam means within the housing means for rotation of the cam means from an at-rest position counterclockwise to a first deflected position and clockwise to a second deflected position; switch means mounted within the housing means and adapted to be engaged by and actuated by the cam means when the cam means is in either of said deflected positions, said switch being unactuated when said cam means is in the at-rest position; finger means mounted on the cam meanns and extending through the tube slot into the interior of the tube; a carrier moving in either direction through the tube striking the finger means thereby rotating said cam means to one of said two deflected positions for actuating the switch means; and said finger means being formed of flexible, semi-rigid wear resistant material composed of an elastomer impregnated woven fabric, whereby the finger means has sufficient flexibility to absorb carrier impact and sufficient rigidity to rotate the cam means when struck by a moving carrier.

2. The construction defined in claim 1 in which the flexible wear resistant material comprises neoprene impregnated cotton duck fabric.

3. The construction defined in claim 1 in which the cam means includes hub means through which the pivot pin means is journaled; the cam means also including a flat cam surface spaced from the axis of the pivot pin means and extending parallel with the axis of the tube, and a pair of curved cam surfaces connected to the ends of said flat surface; in which said curved surfaces are connected to the hub means; and in which the switch means engages an intermediate area of the flat cam surface when the cam means is in the at-rest position.

4. The construction defined in claim 3 in which the switch means includes a lever arm, in which roller means is mounted on the lever arm, and in which said roller means moves along at least the flat cam surface to actuate the switch means when the .cam means moves between the at-rest and deflected positions.

5. The construction defined in claim 4 in which ear means extend from the hub means toward the tube slot; and in which the finger means flexible material is mounted on the ear means and projects beyond the ear means through the tube slot into the path of a carrier when the cam means is in the at-rest position.

6. The construction defined in claim 3 in which the switch means includes a lever arm; in which said lever arm is moved by the flat cam surface as the cam means rotates from the at-rest position to a deflected position to actuate the switch means; and in which said lever arm engages one of the curved cam surfaces after actuation of the switch means preventing continued movement of the lever arm with respect to the switch by the rotation of the cam means.

7. The construction defined in claim 1 in which bracket means is mounted within the housing; and in which the switch means and cam means are mounted in spaced relationship with respect to each other on the bracket means.

8. The construction defined in claim 1 in which spring means is operatively connected to the cam means to return the cam means to at-rest position after the finger means is struck by a passing carrier which moves the cam means to a deflected position.

9. The construction defined in claim 8 in which the spring means is a coil tension spring, one end of which is fixed with respect to the housing and the other end of which is connected to the midpoint of the flat cam surface for movement therewith; and in which the axis of said coil spring lies in a plane extending through the pivotal axis of the cam means and contact finger means when the cam means is in the at-rest position.

10. Detector construction for detecting the passage of a carrier moving through a pneumatic tube of a type in which a slot is formed in the tube including, generally airtight housing means mounted on the pneumatic tube covering the tube slot; cam means; pin means pivotally mounting the cam means within the housing means for moving the cam means between at-rest and a plurality of deflected positions, the axis of said pin means extending transversely with respect to the axis of the pneumatic tube; the cam means including a flat cam surface and a pair of curved cam surfaces connected to and extending from the ends of said flat surface; the flat cam surface being spaced from the pivot pin means with the plane of said flat surface being parallel with the tube axis when in the at-rest position; switch means mounted within the housing; said switch means including an actuating lever arm, said lever arm operatively engaging the straight cam surface when the cam means is in the at-rest position; finger means mounted on the cam means and extending from the cam means through the tube slot into the tube; a carrier moving in either direction through the tube striking the finger means thereby rotating the cam means to a deflected position; coil spring means having opposite ends, one end being fixed with respect to the housing and the other end being connected to the midpoint of the flat cam surface; and the longitudinal axis of said coil spring means lying in a plane extending through the midpoint of the flat cam surface, through the axis of the pivot pin means and through the carrier contact finger means, when the cam means is in the at-rest position; whereby the finger means when struck by a carrier, povots the cam means with the flat cam surface rotating about the pin means and moving the switch means lever arm actuating the switch means, and whereby the spring means returns the cam means to the at-rest position after actuation of the switch means and passage of the carrier.

11. The construction defined in claim 10 in which the switch means lever arm engages one of the curved cam surfaces after actuation of the switch means eliminating further movement of the lever arm by the continued rotation of the cam means.

12. The construction defined in claim in which the stop means are formed on the tube; and in which said carrier contact finger means is formed of flexible, semistop means engages the curved cam surfaces to limit rigid elastomer impregnated woven fabric. the pivotal movement of the cam means.

13. The construction defined in claim 10 in which 

1. Detector construction for detecting the passage of a carrier moving through a pneumatic tube of a type in which a slot is formed in the tube including, generally airtight housing means mounted on the pneumatic tube covering the tube slot; cam means; pin means pivotally mounting the cam means within the housing means for rotation of the cam means from an at-rest position counterclockwise to a first deflected position and clockwise to a second deflected position; switch means mounted within the housing means and adapted to be engaged by and actuated by the cam means when the cam means is in either of said deflected positions, said switch being unactuated when said cam means is in the at-rest position; finger means mounted on the cam meanns and extending through the tube slot into the interior of the tube; a carrier moving in either direction through the tube striking the finger means thereby rotating said cam means to one of said two deflected positions for actuating the switch means; and said finger means being formed of flexible, semi-rigid wear resistant material composed of an elastomer impregnated woven fabric, whereby the finger means has sufficient flexibility to absorb carrier impact and sufficient rigidity to rotate the cam means when struck by a moving carrier.
 2. The construction defined in claim 1 in which the flexible wear resistant material comprises neoprene impregnated cotton duck fabric.
 3. The construction defined in claim 1 in which the cam means includes hub means through which the pivot pin means is journaled; the cam means also including a flat cam surface spaced from the axis of the pivot pin means and extending parallel with the axis of the tube, and a pair of curved cam surfaces connected to the ends of said flat surface; in which said curved surfaces are connected to the hub means; and in which the switch means engages an intermediate area of the flat cam surface when the cam means is in the at-rest position.
 4. The construction defined in claim 3 in which the switch means includes a lever arm, in which roller means is mounted on the lever arm, and in which said roller means moves along at least the flat cam surface to actuate the switch means when the cam means moves between the at-rest and deflected positions.
 5. The construction defined in claim 4 in which ear means extend from the hub means toward the tube slot; and in which the finger means flexible material is mounted on the ear means and projects beyond the ear means through the tube slot into the path of a carrier when the cam means is in the at-rest position.
 6. The construction defined in Claim 3 in which the switch means includes a lever arm; in which said lever arm is moved by the flat cam surface as the cam means rotates from the at-rest position to a deflected position to actuate the switch means; and in which said lever arm engages one of the curved cam surfaces after actuation of the switch means preventing continued movement of the lever arm with respect to the switch by the rotation of the cam means.
 7. The construction defined in claim 1 in which bracket means is mounted within the housing; and in which the switch means and cam means are mounted in spaced relationship with respect to each other on the bracket means.
 8. The construction defined in claim 1 in which spring means is operatively connected to the cam means to return the cam means to at-rest position after the finger means is struck by a passing carrier which moves the cam means to a deflected position.
 9. The construction defined in claim 8 in which the spring means is a coil tension spring, one end of which is fixed with respect to the housing and the other end of which is connected to the midpoint of the flat cam surface for movement therewith; and in which the axis of said coil spring lies in a plane extending through the pivotal axis of the cam means and contact finger means when the cam means is in the at-rest position.
 10. Detector construction for detecting the passage of a carrier moving through a pneumatic tube of a type in which a slot is formed in the tube including, generally airtight housing means mounted on the pneumatic tube covering the tube slot; cam means; pin means pivotally mounting the cam means within the housing means for moving the cam means between at-rest and a plurality of deflected positions, the axis of said pin means extending transversely with respect to the axis of the pneumatic tube; the cam means including a flat cam surface and a pair of curved cam surfaces connected to and extending from the ends of said flat surface; the flat cam surface being spaced from the pivot pin means with the plane of said flat surface being parallel with the tube axis when in the at-rest position; switch means mounted within the housing; said switch means including an actuating lever arm, said lever arm operatively engaging the straight cam surface when the cam means is in the at-rest position; finger means mounted on the cam means and extending from the cam means through the tube slot into the tube; a carrier moving in either direction through the tube striking the finger means thereby rotating the cam means to a deflected position; coil spring means having opposite ends, one end being fixed with respect to the housing and the other end being connected to the midpoint of the flat cam surface; and the longitudinal axis of said coil spring means lying in a plane extending through the midpoint of the flat cam surface, through the axis of the pivot pin means and through the carrier contact finger means, when the cam means is in the at-rest position; whereby the finger means when struck by a carrier, povots the cam means with the flat cam surface rotating about the pin means and moving the switch means lever arm actuating the switch means, and whereby the spring means returns the cam means to the at-rest position after actuation of the switch means and passage of the carrier.
 11. The construction defined in claim 10 in which the switch means lever arm engages one of the curved cam surfaces after actuation of the switch means eliminating further movement of the lever arm by the continued rotation of the cam means.
 12. The construction defined in claim 10 in which the carrier contact finger means is formed of flexible, semi-rigid elastomer impregnated woven fabric.
 13. The construction defined in claim 10 in which stop means are formed on the tube; and in which said stop means engages the curved cam surfaces to limit the pivotal movement of the cam means. 